3d semiconductor devices and structures

ABSTRACT

A 3D device, the first level including first transistors and a first interconnect; a second level with second transistors overlaying the first level; a third level with third transistors overlaying the second level; a plurality of electronic circuit units (ECUs), where each ECU includes a first circuit with a portion of the first transistors, where each of the ECUs includes a second circuit including a portion of the second transistors, where each of the plurality of ECUs includes a third circuit, which includes a portion of the third transistors, where each of the ECUs includes a vertical data bus, where the vertical data bus has between eight pillars and three hundreds pillars, where the vertical data bus provides electrical connections between the first and second circuits, where the third level includes an array of memory cells, and where the second circuit includes a memory control circuit.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This application relates to the general field of Integrated Circuit (IC)devices and fabrication methods, and more particularly to multilayer orThree Dimensional Integrated Memory Circuit (3D-Memory) and ThreeDimensional Integrated Logic Circuit (3D-Logic) devices and fabricationmethods.

2. Discussion of Background Art

Over the past 40 years, there has been a dramatic increase infunctionality and performance of Integrated Circuits (ICs). This haslargely been due to the phenomenon of “scaling”; i.e., component sizessuch as lateral and vertical dimensions within ICs have been reduced(“scaled”) with every successive generation of technology. There are twomain classes of components in Complementary Metal Oxide Semiconductor(CMOS) ICs, namely transistors and wires. With “scaling”, transistorperformance and density typically improve and this has contributed tothe previously-mentioned increases in IC performance and functionality.However, wires (interconnects) that connect together transistors degradein performance with “scaling”. The situation today is that wiresdominate the performance, functionality and power consumption of ICs.

3D stacking of semiconductor devices or chips is one avenue to tacklethe wire issues. By arranging transistors in 3 dimensions instead of 2dimensions (as was the case in the 1990s), the transistors in ICs can beplaced closer to each other. This reduces wire lengths and keeps wiringdelay low and wire.

There are many techniques to construct 3D stacked integrated circuits orchips including:

-   -   Through-silicon via (TSV) technology: Multiple layers of dice        are constructed separately. Following this, they can be bonded        to each other and connected to each other with through-silicon        vias (TSVs).    -   Monolithic 3D technology: With this approach, multiple layers of        transistors and wires can be monolithically constructed. Some        monolithic 3D and 3DIC approaches are described in U.S. Pat.        Nos. 8,273,610, 8,298,875, 8,362,482, 8,378,715, 8,379,458,        8,450,804, 8,557,632, 8,574,929, 8,581,349, 8,642,416,        8,669,778, 8,674,470, 8,687,399, 8,742,476, 8,803,206,        8,836,073, 8,902,663, 8,994,404, 9,023,688, 9,029,173,        9,030,858, 9,117,749, 9,142,553, 9,219,005, 9,385,058,        9,406,670, 9,460,978, 9,509,313, 9,640,531, 9,691,760,        9,711,407, 9,721,927, 9,799,761, 9,871,034, 9,953,870,        9,953,994, 10,014,292, 10,014,318; and pending U.S. Patent        Application Publications and applications, Ser. No. 14/642,724,        Ser. No. 15/150,395, Ser. No. 15/173,686, 62/651,722;        62/681,249, 62/713,345, 62/770,751, 62/952,222, 2020/0013791,        16/558,304; and PCT Applications (and Publications):        PCT/US2010/052093, PCT/US2011/042071 (WO2012/015550),        PCT/US2016/52726 (WO2017053329), PCT/US2017/052359        (WO2018/071143), PCT/US2018/016759 (WO2018144957), and        PCT/US2018/52332 (WO 2019/060798). The entire contents of the        foregoing patents, publications, and applications are        incorporated herein by reference.    -   Electro-Optics: There is also work done for integrated        monolithic 3D including layers of different crystals, such as        U.S. Pat. Nos. 8,283,215, 8,163,581, 8,753,913, 8,823,122,        9,197,804, 9,419,031, 9,941,319, and 10,679,977. The entire        contents of the foregoing patents, publications, and        applications are incorporated herein by reference.

In addition, the entire contents of U.S. Pat. No. 10,014,318, U.S.patent application publication 2018/0350823 and U.S. patent applications62/963,166, 62/963,270, 62/983,559, 62/986,772, 63,108,433, 63/118,908,63/123,464 are incorporated herein by reference.

Additionally the 3D technology according to some embodiments of theinvention may enable some very innovative IC devices alternatives withreduced development costs, novel and simpler process flows, increasedyield, and other illustrative benefits.

SUMMARY

The invention relates to multilayer or Three Dimensional IntegratedCircuit (3D IC) devices and fabrication methods. Important aspects of 3DIC are technologies that allow layer transfer. These technologiesinclude technologies that support reuse of the donor wafer, andtechnologies that support fabrication of active devices on thetransferred layer to be transferred with it.

In one aspect, a 3D device, said device comprising: a first levelcomprising first transistors, said first level comprising a firstinterconnect; a second level comprising second transistors, said secondlevel overlaying said first level; a third level comprising thirdtransistors, said third level overlaying said second level; a pluralityof electronic circuit units (ECUs), wherein each of said plurality ofECUs comprises a first circuit, said first circuit comprising a portionof said first transistors, wherein each of said plurality of ECUscomprises a second circuit, said second circuit comprising a portion ofsaid second transistors, wherein each of said plurality of ECUscomprises a third circuit, said third circuit comprising a portion ofsaid third transistors, wherein each of said ECUs comprises a verticaldata bus, wherein said vertical data bus comprises greater than eightpillars and less than three hundreds pillars, wherein said vertical databus provides electrical connections between said first circuit and saidsecond circuit, wherein each of said ECUs comprises vertical controllines, wherein said vertical control lines comprise more than eighthundreds pillars, and wherein said vertical control lines provideelectrical connections between said second circuit and said thirdcircuit.

In another aspect, a 3D device, the device comprising: a first levelcomprising first transistors, said first level comprising a firstinterconnect; a second level comprising second transistors, said secondlevel overlaying said first level; a third level comprising thirdtransistors, said third level overlaying said second level; a pluralityof electronic circuit units (ECUs), wherein each of said plurality ofECUs comprises a first circuit, said first circuit comprising a portionof said first transistors, wherein each of said plurality of ECUscomprises a second circuit, said second circuit comprising a portion ofsaid second transistors, wherein each of said plurality of ECUscomprises a third circuit, said third circuit comprising a portion ofsaid third transistors, wherein each of said ECUs comprises a verticaldata bus, wherein said vertical data bus comprises greater than eightpillars and less than three hundreds pillars, wherein said vertical databus provides electrical connections between said first circuit and saidthird circuit, wherein each of said ECUs comprises vertical controllines, wherein said vertical control lines comprise more than eighthundreds pillars, and wherein said vertical control lines provideelectrical connections between said second circuit and said thirdcircuit.

In another aspect, a 3D device, the device comprising: a first levelcomprising first transistors, said first level comprising a firstinterconnect; a second level comprising second transistors, said secondlevel overlaying said first level; a third level comprising thirdtransistors, said third level overlaying said second level; a pluralityof electronic circuit units (ECUs), wherein each of said plurality ofECUs comprises a first circuit, said first circuit comprising a portionof said first transistors, wherein each of said plurality of ECUscomprises a second circuit, said second circuit comprising a portion ofsaid second transistors, wherein each of said plurality of ECUscomprises a third circuit, said third circuit comprising a portion ofsaid third transistors, wherein each of said ECUs comprises a verticaldata bus, wherein said vertical data bus comprises greater than eightpillars and less than three hundreds pillars, wherein said vertical databus provides electrical connections between said first circuit and saidsecond circuit, wherein said third level comprises an array of memorycells, and wherein said second circuit comprises a memory controlcircuit.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention will be understood and appreciatedmore fully from at least the following detailed description, taken inconjunction with the drawings in which:

FIG. 1 is an example illustration of a 7 nm 6T SRAM bit-cell layout;

FIG. 2 is an example illustration of a memory structure having memoryunits laid out in a 2D repeating pattern;

FIGS. 3A-3D are example illustrations of various arrangements andcustomizations of the 2D repeating pattern memory structure of FIG. 2;

FIGS. 4A-4C are example illustrations of cut views of FIGS. 3B-3Dillustrating various unit to unit and within unit connectivity;

FIGS. 5A-5E are example illustrations of word-line pin/pad connectivitylay outs and bit-line pin/pad connectivity lay outs;

FIG. 6 is an example illustration of extending the memory layout conceptto a multi-level memory structure;

FIG. 7A is an example illustration of FIG. 43E of U.S. application Ser.No. 16/558,304;

FIG. 7B is an example illustration of a memory unit that includes memoryand memory controller;

FIG. 7C is an example illustration of 4 memory units of FIG. 7B formedas an array;

FIG. 7D is an example illustration of a wafer sized array of memoryunits;

FIGS. 7E-7G are example illustrations of cut views of a formationprocess of memory strata which can be stored and then later bonded toother device structures to form systems;

FIG. 8 is an example illustration of an overall process flow ofdesigning the logic and memory;

FIGS. 9A-9G are example illustrations of a 3D strata formation flowwhich could form a 3D compute device;

FIGS. 10A-10D are example illustrations of various power deliverysubstrate architectures to effectively deliver power multiple levels ofactive devices via heterogeneous integrations;

FIG. 11 is an example table illustrating wafer processing costs arehighly dependent on the type of process line used;

FIGS. 12A-12B are example illustrations of a coupling level ready to behybrid bonded to an over the circuit pin/pad structure;

FIGS. 13A-13B are example illustrations of phased integrations ofvarious 3D systems and the forming of various M-levels;

FIGS. 14A-14E are example illustrations various level integrations toform various types of 3D systems;

FIGS. 15A-15D are example illustrations of DieM-Levels being part of a3D system with photonic X-Y connectivity;

FIGS. 16A-16E are example illustrations of various heat removaltechniques and structures which may be built-in to 3D systems; forexample, SubstrateM-Levels in a 3D system could include multiple computelevels and memory levels with X-Y connectivity levels in-between, whilethe system heat could be managed by liquid cooling; and

FIGS. 17A-17D are example illustrations of full M-Levels being formedvia multiple steps of simple bonding and thinning, and then using TSVprocessing to form the vertical bus pillars through the levels-stack andthen form the pin/pads.

DETAILED DESCRIPTION

An embodiment of the invention is now described with reference to thedrawing figures. Persons of ordinary skill in the art will appreciatethat the description and figures illustrate rather than limit theinvention and that in general the figures are not drawn to scale forclarity of presentation. Such skilled persons will also realize thatmany more embodiments are possible by applying the inventive principlescontained herein and that such embodiments fall within the scope of theinvention which is not to be limited except by any appended claims

Some drawing figures may describe process flows for building devices.The process flows, which may be a sequence of steps for building adevice, may have many structures, numerals and labels that may be commonbetween two or more adjacent steps. In such cases, some labels, numeralsand structures used for a certain step's figure may have been describedin the previous steps' figures.

The use of layer transfer in the construction of a 3D IC based systemcould enable heterogeneous integration where each of strata may includeone or more of MEMS sensor, image sensor, CMOS SoC, volatile memory suchas DRAM and SRAM, persistent memory, and non-volatile memory such asflash and OTP. Such could include adding memory control circuits, alsoknown as peripheral circuits, on top or below a memory array. The memorystrata may contain only memory cells but not control logic, thus thecontrol logic may be included on a separate stratum. Alternatively, thememory strata may contain memory cells and simple control logic wherethe control logic on that stratum may include at least one of decoder,buffer memory, sense amplifier. The circuits may include the chargepumps and high voltage transistors, which could be made on a stratausing silicon transistors or other transistor types (such as SiGe, Ge,CNT, etc.) using a manufacturing process line that is different than thelow voltage control circuit manufacturing process line. The analogcircuits, such as for the sense amplifiers, and other sensitive linearcircuits, could also be processed independently and be transferred overto the 3D fabric. Such 3D construction could include “Smart Alignment”techniques presented in this invention or leverage the repeating natureof the memory array to reduce the impact of the wafer bondermisalignments on the effectiveness of the integration.

In patents such as, for example, U.S. patent application Ser. No.15/173,395, layer transfer techniques called ELTRAN (epitaxial layertransfer) are presented and may be part of the formation process of a3DIC. The ELTRAN technique utilizes an epitaxial process or processesover porous layers. Alternatively other epitaxial based structures couldbe formed to support layer transfer techniques by leveraging the etchselectivity of these epitaxial layers, such as the very high etchselectivity of SiGe vs. Silicon, and variations such as Silicon (singlecrystal or poly or amorphous), SiGe (mix of silicon and Germanium), Pdoped silicon, N doped silicon, etc. Alternately, these layer(s) couldbe combined with types of detachment processes, such as ‘coldsplitting,’ for example the Siltectra stress polymer and low temperatureshock treatment, to provide a thin layer transfer process.

Recently it become a very attractive concept for processing gate allaround horizontal transistors and has become the target flow for nextgeneration devices such as the 5 nm technology node. Some of the work inrespect to selective etching of SiGe vs. silicon has been presented in apaper by Jang-Gn Yun et al. titled: “Single-Crystalline Si Stacked Array(STAR) NAND Flash Memory” published in IEEE TRANSACTIONS ON ELECTRONDEVICES, VOL. 58, NO. 4, April 2011, and a more recent work by K. Wostynet al. titled “Selective Etch of Si and SiGe for Gate All-Around DeviceArchitecture” published in ECS Transactions, 69 (8) 147-152 (2015), andby V. Destefanis et al. titled: “HCl Selective Etching of Sil-xGexversus Si for Silicon On Nothing and Multi Gate Devices” published inECS Transactions, 16 (10) 427-438 (2008), all of the forgoingincorporated herein by reference. Since the SiGe over Si substrateprocess is becoming mature, this facilitates using a SiGe layer as asacrificial layer for production worthy 3D layer transfer.

In at least U.S. Pat. No. 8,669,778, incorporated herein by reference,in respect to at least FIG. 22, a technique to have a generic memoryarray such as SRAM, DRAM, FRAM, RRAM, or MRAM customized for specificapplications and be integrated as part of a 3D device flow waspresented. In at least U.S. Pat. No. 9,021,414, incorporated herein byreference, flows and techniques to adapt an electronic design automation(“EDA”) tool for such a 3D structure are presented. In at least U.S.patent application Ser. No. 16/558,304, incorporated herein byreference, in respect to FIG. 21A to FIG. 25J, technique(s) to have ageneric memory array integrated with logic utilizing hybrid bonding aspart of a 3D device flow were presented. Herein a further variation ofthese concepts is presented. The 3D device could include a custom designlogic level for which a memory level is integrated by use of a 3Dintegration using, for example, hybrid bonding. The memory level couldbe made fully custom to match the underlying custom logic, or by using ageneric memory level, as presented herein, which has been customized byfew added step to match the underlying custom logic. The memory levelcould be formed as an array of units in which the units are an array ofbit-cells. The underlying custom logic could include the memory controlcircuit such as decoders and sense amplifiers.

In the following memory stacking alternatives, a few considerations areconsidered as important drivers. First, the objective is to maintain orminimize overall investment in using the memory stacking for customdevices. Accordingly, the memory array could be designed as a genericstructure to be customized by very few custom steps, such as one or twometal layers and their associated via layer(s). Second, the genericmemory structure uses conventional and simple copper interconnects whichare usually defined by Chemical Mechanical Polishing-“CMP”, and notetching. In other words, the generic memory structure could be suppliedby dedicated suppliers such as a semiconductor foundry and the genericmemory structure can be purchased and customized by many customers andaccording to their demand at reduced cost for masks and othernon-recurring costs (“NRE”).

Accordingly, the generic memory structure could be designed as an arrayof units. Each unit could be a small two-dimensional array of bit cellsin the wafer plane. Later, if a product or customer requires a higherbit-cell density than the bit-cell density of a 2D single die, multiplegeneric memory wafers could be stacked to form a 3D stacked genericmemory structure. As the identically designed and processed genericmemory wafers are stacked, the memory unit is repeated in the verticaldirection or along the out of wafer plane. Typically the number of rowsin a unit could range from 32 to 1028 and the number of columns in theunit could range from 32 to 1028. In order to provide the flexibilityand versatility to the customer with minimally compromising the cost,power, and performance, relatively smaller unit sizes such as 32×32 or64×64 may be favored rather than the unit sizes such as 512×512. Herein,the smallest size of the unit will be referred as a ‘primitive unit’. Ifthe generic memory wafer shall be considered for the 3D stacked genericmemory wafer, the neighboring primitive unit could have some additionalspace for through silicon vias or through layer vias. The customizationin terms of the memory unit size could be offered by adding a few customprocess steps on top of the generic memory wafer before the waferstacking step. The customization step could be an additionalmetallization step processed on the generic memory wafer, which bridgesand stitches a few units into the desired size of the memory structure.The multiple primitive units stitched together to form a target sizewill be referred as a ‘stitched unit’. For example, four units of 32×32primitive units can be connected to form a 64×64 stitched unit. Inaddition to the stitching process, a pin pad formation step could beincluded as part of these extra metal customization process steps. Thenthe customized memory wafer could be flipped and bonded, using forexample hybrid bonding, to the logic substrate and form connections topre-defined pads at the logic substrates connecting the memory to thelogic.

The smallest memory structure could be designed with consideration ofthe bit-cell size and the precision of the hybrid bonding defining theminimum pitch and size for the bonding pads. The unit could be designedaccording to such a smallest memory structure or even smaller allowingmore flexible placement and grid granularity.

Let's consider a bit-cell having width W and length L of total area W*L.Let's assume a hybrid bonding process with minimum pitch of Hrepresenting area for one connection H*H, wherein the area for oneconnection includes actual pad and space for the bonding. Let's assumethe memory to be a 6T SRAM having one wordline for each cell width andtwo bit-lines for every bit-cell length. Let's assume the minimum arrayto have m cells along its width and n cells along it length. Accordinglythe following formula represents the requirement for such a structure:

m*W*2n*L>=m*H*H+n*H*H

As we can see the number of pads, and accordingly the required area forthe pads, are growing according to m+n while the unit array area isgrowing by m*n. Accordingly given specific numbers and a choice ofaspect ratio, a minimum array size could be defined for a specific caseof bit-cell and with a hybrid bonding process.

As an example, recent reports on hybrid bonding, such as by: Jouve, A.,et al. “1 μm pitch direct hybrid bonding with <300 nm Wafer-to-Waferoverlay accuracy.” 2017 IEEE SOI-3D-Subthreshold MicroelectronicsTechnology Unified Conference (S3S). IEEE, 2017; and Global Foundriespress release of Aug. 7, 2019 titled “GLOBALFOUNDRIES and ArmDemonstrate High-Density 3D Stack Test Chip for High Performance ComputeApplications, indicate a hybrid bonding of 1 micron pitch (H=1 micron).

An example of a 7 nm 6T SRAM bit-cell layout is illustrated in FIG. 1showing a W=108 nm and L=250 nm. Following the above formula and anapproximately square memory structure, the smallest memory structurethat could be used for hybrid bonding could have:

m˜100 and n˜85.

FIG. 2 illustrates such an exemplary memory structure having primitiveunits 202 which for such an example could be set as the minimum arrayhaving an ˜100*85 bit cell. The units could be placed with a bit-cellsize space 204 between them forming a two dimensional repeating pattern200 of generic memory.

FIG. 3A illustrates four units 202 of the array of units such as in FIG.2. These four units are arranged in a 2×2 configuration example.

FIG. 3B illustrates the four generic units 202 being customized tofunction as a memory structure by forming ‘bridges’ 304 (or strappingconnections) between them such that the wordlines and the bitlines areconnected so to control the 2×2 memory structure. The bridges connectthe word-lines and bit-lines of adjacent units. The bridges could becopper, tungsten or other conductive metal or conductive material whichis as conductive as copper or better.

FIG. 3C illustrates the further customization example attained by addingpads or pins 306 in preparation for the following step of hybridbonding. The pads or pin could be copper, aluminum or other metal. Thepad or pin 306 layer can be processed at the same step of the bridgelayer. Alternatively, the pad or pin 306 layer could be formed on anupper level compared to the bridge layer so when the pad and pin 306layers are exposed, the bridge layer resides inside the dielectriclayer.

FIG. 3D illustrates the extension of the structure showing an additional2×2 memory structure (for a total of two 2×2 memory structures) and thespace 308 between them without bridges. Each 2×2 memory structure hasfour generic units 202 in this example.

FIG. 4A illustrates a cut view in the area marked by ellipse 322 of FIG.3A. FIG. 4A shows a gap 450 in memory control line 402. Memory controlline 402 could be a bit-line or a word-line, or in some cases anothertype of memory control line. The memory control line 402 is extendedoutside of the outer boundary of bit cell array.

FIG. 4B illustrates a cut view in the area marked by ellipse 302 of FIG.3C. FIG. 4B illustrates bridge 404 with vias 409 linking the gap 450 andconnecting the control line 402 of one unit 202 with another controlline 402 from another unit 202. Pad/pins 406 and 408 show potentialconductive hybrid bonding spots. Exemplary via 407 [for example, a thrusilicon via (TSV) or a through layer via (TLV)] may connect pad/pins 406to an underlying control line within an exemplary unit 202. As well, anelectrically conducive connection from a pad/pin 408 thru via 407 toanother control line 410 coming from the edge is further illustrated inFIG. 4D.

FIG. 4C illustrates a cut view in the area mark by ellipse 312 of FIG.3D. The figure illustrates via 412 connecting the control line 404 fromthe unit edge with wire 414 and vias 407 and 412 to the pad/pin 406 forfuture bonding. FIGS. 4A, 4B and 4C illustrate a portion of the edge ofgeneric units 202 and are exemplary in nature. Engineering designchoices may create many variations of the connectivity conceptspresented herein to optimize speed, power and cost of the envisionedsystem/device. For example, the pad/pin, via, control line segments,etc. shown in FIGS. 4A-4C do not need to be symmetric with respect togap 450. Each portion of units 202 may have a completely differentconnectivity. As well, the connections between units 202 may beprogrammable, for example, by laser blowing or fusing fuses, or may beelectrically programmed to be a conductive connection by an anti-fuse,or non-conductive by a fuse.

FIG. 5A-5C illustrates an example of a memory unit with a 3D pin/padsconnectivity structure which is using two metal layers and a pin/padslayer.

FIG. 5A illustrates the pin/pads layer on top of a grid illustrating theunderlying bit-lines 502 having pitch 510 (“BLP”), and word-lines 504having pitch 509 (“WLP”). The hybrid bonding pin/pad pitch is 501 in W-Edirection and 503 in the N-S direction, about 4 times courser than BLPand WLP, The fundamental concept is to re-distribute control lines whichmay have a tight pitch requirement into a two-dimensional metal padarray in a larger pitch to accommodate the hybrid bonding capability. Inthis example the bit-lines are the memory top metal in W-E cardinal 500direction and the word-lines underneath in N-S cardinal 500 direction.In this example the memory cell size is about 2×BLP*WLP−two grid squareif complementary cells requiring BL and BL/ such as SRAM or aboutBLP*WLP−one grid square if the cell has only one BL such as DRAM, MRAM,PRAM, or RRAM. For simplicity, one grid squared is assumed to be onegrid square for forthcoming explanation. The bonding alignment suggestsa pad/pin of about two BLP by two WLP or 2×2 grid square 505, 507 whichsuggests a total area for one pad/pin of a 4×4 grid square. In otherwords, the one pad/pin occupies 16 bit cell areas; 4 bit cell areas ofpin/pad and 12 bit cells are needed for space. In this example eachmemory cell has one word-line and one bit-line, such as is found in DRAMbit cells. The calculation for the minimum unit size could be adapted toother type memory cells accordingly as in the following. For thisexample the unit aspect ratio is about one-square unit. The BLP is aboutthe same as WLP or P for the following calculation. Accordingly the areafor one pin/pad is 4×4×P²=16P², the number of word-lines could be equalto the number of bit-lines or m for a square unit structure, than theformula suggests:

16P ²*(m+m)<=mP*mP, or 32<=m.

Accordingly the example of FIG. 5A illustrates a smallest unit of 32bit-lines by 32 word-lines.

FIG. 5A illustrates 32 pin/pads 507 for the bit-line connectivity forwhich the first 16 bit-line addresses are numbered 508, and 32 pin/pads505 for the word-line connectivity. It also illustrates with dashedlines 506 allocating the top surface to four zones, two for the pin/padsfor the word-line connectivity and two for the bit-line connectivity.The specific pin/pad arrangement of FIGS. 5A-5C are exemplary, andspecific arrangements may be designed according to engineering tradeoffssuch as lithographic and bonding alignment accuracy and precision,critical speed nets, memory cell size and aspect ratio, etc.

FIG. 5B illustrates metal connection of the bit-lines. There isconnection between each bit-line to one corresponding pin/pad. Theconnections are split into two groups. The even numbered 526 bit lineswhich are connected from the South using side via 516 while the oddnumbered are from the North side. This leverages the availability ofeach bit-line on both sides of the unit. The connectivity layout is onlyan illustration. A qualified layout could be designed by a layoutartisan in the art taking into account the design rules for the specificprocess. Such a layout could include extending the unit size toaccommodate lay out limitations in such specific cases. In FIG. 5B thetop metal is allocated to the pad/pins 522, 524. Connected with via 520to the underlying metal layer 514 oriented W-E, connected with via 518to the metal layer underneath 512 which is oriented S-N in FIG. 5B.

The connectivity layout (not shown) for the bit-line could be made in asimilar fashion in the area left for it, or leverage the availability ofthe bit-lines oriented W-E being at the top of the memory array usingdirect vias rather than West, East side's access vias.

FIG. 5C illustrates the top three connectivity layers of FIG. 5B withoutthe grid, for better visibility of the word-lines pin/pad connectivitylay out. The drawing symbol legends between FIGS. 5B and 5C are thesame.

Although not drawn, many memory bit cells require power and groundlines, for example, such as SRAM. It should be understood that thebonding pad for the power and ground are allocated on top of bridgeregion 304 of Fig. The power and ground lines are often biased at staticvoltage without row or column individually control, the power and groundlines from multiple rows or columns are grouped together so only a fewpads would be required.

The top surface of the logic wafer would have a pad/pin layout which isreciprocal to the memory wafer or die. The pad layout for the logicwafer and the memory wafer would be mirrored so that they can beproperly F2F bonded and electrically connected later. The pad/pin of thelogic wafer would be connected to the sense amplifier for bit-line andmultiplexer for word-line pad.

Another alternative is to have a bit larger unit size to allow a regularpin/pad over the unit connectivity. Such could allow one metal layer forthe routing and another one for the pin/pads layer. To illustrate thisalternative, the unit structure of FIG. 5A and with betterhybrid-bonding pitch (“H”) as is illustrated in FIG. 5D. The bonding padpitch 541, 543 including pad/pin 547 is, for example, three times largerthan the wordline pitch WLP 549 and the bitline pitch BLP 550 of memoryarray. The hybrid bonding connectivity structure resemble the onereferenced in PCT/US2017/052359, incorporated herein by reference, asrelated to its FIG. 21A-21C, folded over the memory unit as isillustrated in FIG. 5D herein. The ratio, H/BLP, between the hybridbonding pitch H and the bitline pitch BLP, could derive the number(rounding up) of columns of bonding pad/pin for the bitlines as isillustrated in FIG. 5D. Similarly, the ratio H/WLP, between hybridbonding pitch H and the wordline pitch WLP, could drive the number(rounding up) of rows bonding pad/pin for the wordlines as isillustrated in FIG. 5D. As a result, the number of rows and columns forWL and the number of rows and columns for BL are respectivelydetermined. So the top surface of the unit could be marked to foursimilar size quadrants by the N-S dashed line 545 and the W-E dashedline 546. The N-E quadrant 542 could be used for bonding pads/pin forhalf of the bitlines 554 while the W-S could be used for bondingpads/pin for the other half of the bitlines 554, and in similar way forthe wordlines 552, W-N quadrant for the first half and the S-E for theother half.

To assess what could be the smaller unit size for such pin/padsconnectivity, the following considerations could be addressed. Thedashed line 556 represent the South direction edge of the N-E quadrantstructure, while the dashed line 557 represent the North edge of the S-Equadrant connectivity structure. The distance between these structures558 is required to avoid these structures getting too close. The length(in N-S direction) of the N-E quadrant structure is about ˜n/2*BLP+H. Inhere, n is the number of bitlines in the unit. The width (in N-Sdirection) of the S-E quadrant structure is about ˜H/WLP (round up)*H.For simplicity, let's assume that the wordline pitch is about equal tothe bitline pitch and could be symbolized as P. The unit size in N-Sdirection is about n*P. Accordingly the formula representing thecondition regarding 558 is: H/P*H+H+n/2*P<n*P which could be written as:n>2H²/P²+2H/P. For example, let's assume H=1 micron and P=0.1 micronthan n>220. Accordingly a memory array that is structured as array ofunits sized 200μ*200μ with a control lines pitch of 0.1μ would haveenough top of the unit area to form a pin/pads connectivity structuresuch as illustrated in FIG. 5D having n˜2,000>>220. FIG. 5E is theillustration of FIG. 5D after removing the grid and other marks andadding marks for the borders of the underlying memory unit 560

FIG. 6 illustrates extending the concept to a multi-level memorystructure. Such could be utilized in cases in which the memoryrequirements are very high and a single level of memory would not offerenough memory. FIG. 6 is similar to FIG. 22F of U.S. application Ser.No. 16/558,304 incorporated herein by reference. The vertical pillars ofthe global control lines such as 2246 and 2258 of FIG. 22F (of Ser. No.16/558,304) are replaced with two sets of vertical pillars 645, 646 asreplacement of 2246, and 655, 656 as replacement of 2258, and so forth.And the bridging concept of FIG. 4B or the pad/pin extension for bondingof FIG. 4C could be used for the customization of multi-levels memorystructure. The per-level selects 647, 657 could be connected to thecontrol logic to enable full control of the specific level selected.

FIG. 7A is a copy of FIG. 43E of U.S. application Ser. No. 16/558,304,incorporated herein by reference. FIG. 7A illustrates a multi-leveldevice that could comprise, logic levels, customize memory levels aspresented herein to support such logic level as cache 1, cache 2 or lastlevel cache type memory, additional levels of memory and levels ofmemory controls including decoding and sense amplifier circuits, theselevels could be in the form of multi-level stacks of high speed memorysuch as DRAM, memory structures such as 3D NOR and storage structuressuch as 3D NAND. Additionally, the level(s) of global X-Yinterconnection could utilize electromagnetic waves over transmissionlines or wave-guides with the supporting RF or optical circuits. Thevarious levels could include feed through connections to allow acrosslevel vertical connectivity. The use of layer transfer in theconstruction of such a 3D IC based system could enable heterogeneousintegration wherein each strata/layer/level may include, for example,one or more of MEMS sensor, image sensor, CMOS SoC, volatile memory suchas DRAM and SRAM, persistent memory, Ferroelectric Memory andnon-volatile memory such as flash and OTP. Such could include addingmemory control circuits, also known as peripheral circuits, on top orbelow a memory array. The memory strata may contain only memory cellsbut not control logic, thus the control logic may be included on aseparate stratum. Alternatively, the memory strata may contain memorycells and simple control logic where the control logic on that stratummay include at least one of decoder, buffer memory, sense amplifier. Theperipheral/control circuits may include the charge pumps and highvoltage transistors, which could be made on a strata using silicontransistors or other transistor types (such as SiGe, Ge, CNT, etc.)using a manufacturing process line that may be, and often is, differentthan the low voltage control circuit manufacturing process line. Theanalog circuits, such as for the sense amplifiers, and other sensitivelinear circuits could also be processed independently and be layertransferred over to the 3D fabric. Such 3D construction could includethe “Smart Alignment” techniques presented in this invention orincorporated references, or leverage the repeating nature of the memoryarray to reduce the impact of the wafer bonder misalignment on theeffectiveness of the integration. Such as presented in PCT/US2017/052359(WO2018/071143), incorporated herein by reference in its entirety.Specifically for this discussion, in respect to its FIG. 11A to FIG.12J, or using hybrid bonding techniques as presented in respect to itsFIG. 20A to FIG. 25J. Hybrid bonding between levels reduces the processsteps required in such a 3D integration but provides less flexibilityfor overcoming the misalignment challenge. “Smart Alignment” techniquesallow overcoming such alignment challenges but will require via etchesand deposition steps for such levels adding steps to the stackingprocess. The vertical connectivity challenge could be quite differentbetween the various levels in the 3D stack structure. Stacking memorylevels which have no in-level decoders could require verticalconnectivity at word-lines, bit-lines pitch and so forth to thedecoder's level, which is relatively more demanding than theconnectivity of other levels in the stack. Accordingly the stackingprocess could be different to accommodate the alignment requirementbetween these levels. Also the source of alignment error could bedifferent making the error sometimes smaller if the wafers are comingfrom the same process lines such as could be expected for the memorylevels (for example, minimal stepper matching). These choices and the 3Dengineering design could use the various 3D integration techniquespresented herein the incorporated by reference art by an artisan in theart.

The memory strata could include multiple types and memory technologiesand could be placed in various levels of the 3D device structure such asis illustrated in FIG. 7A. It could include high speed memory closer tothe computing logic and high density memories closer to the X-Yinterconnection fabrics. The high density levels could be in the formsimilar to what is known in the industry as 3D NAND, V-NAND, X-pointmemory, or Optane, while the high speed memory could be similar to whatis called 3D NOR-P and presented in PCT/US2018/016759 and 62/952,222,both incorporated herein by reference. The memory stratum could be astructure of arrays of units. FIG. 7B illustrates such unit which couldhave a size of about 0.04 mm², about 0.1 mm², about 0.4 mm², about 0.1mm², about 0.4 mm². Or even larger than about 1 mm². It could astructured array of units such as 2×2, 4×4, 8×8, 32×32, 256×256,1024×1024 or any mix of these numbers such 16×64. The memory level couldinclude the memory control circuits 710, 714 also called memoryperiphery circuits and about 100 feed-through per units 718 to supportvertical connectivity throughout the 3D structure 700. The controlcircuits could be structured so that each memory unit has its owncontrol on top 710 and/or below 714 the memory array 712. Theconnectivity between the memory control and the memory array couldutilize hybrid bonding and pad/pin structure as been presented here inreference to FIG. 5A-5C or other structures such as been presented inthe incorporated by reference art such as in PCT/US2017/052359,incorporated herein by reference, as related to its FIG. 21A-21C. Theconnectivity from the control circuit 714 to the other device level suchas computing logic 716 could be relatively easier as for an area of aunit there could be need for few tens or very few hundreds ofconnections needed as the memory control circuits include the addressbus decoders. So within the units the connectivity needs from the memorycontrol circuits to the memory array, 2D or 3D, could include a fewthousand of connections to the bit-lines and the word-lines about ahundred of connection for the feed-throughs and few tens to a fewhundred for the layer select in the case of 3D memory. The few hundredadditional connections could be added on top of the unit or by it sideas even for pad/pin with 1 micron pitch over a side length of a unitwhich is 200 microns or more will add only single percents of overheadarea to the structure. The memory stratum could be a standard module tobe integrated with other structures to form custom or semi-customproduct. The structure size could be a full wafer or any smallerstructure such as even a single field of even smaller than 100 mm² size,as presented in PCT/US2018/52332, incorporated herein by reference. Theindustry supports stacking with various type of bonding including hybridbonding of wafers or dies. The memory controller could include build intest and redundancy activation to be operated during device set up andoperation. The activation and reporting of these built-in test andredundancy could be included as part of the function of these hundredsof connections and feed-through connections.

The data bus for such a unit could be different for different unitsacross the structure and so could be the size of the units in thestructure. The data bus could be 1, 2, 4, 8, 16, 32 or 64 bits which arecommon in the industry but could also be an extreme wide data bus of fewhundreds or even thousands of bits to support processor designs with anextremely wide data bus, or with additional on chip buffers to increasedata speed from memory to processor level.

FIG. 7C illustrates tiling the unit structure of FIG. 7B thus forming anarray of units 740. Such tiling could be across a full wafer or anyportion of such. FIGS. 7A-7C are side-views along the X-Z 702 direction.FIG. 7D is a planar view along the X-Y 703 direction of a wafer sizedarray of units 704.

The process flow to form full 3D Heterogeneous integration such as isillustrated in FIG. 7A could include a few steps of wafer bonding andsubstrate removal such as been called “cut” using cut-layer or thinningusing grinding and etch which could include using the cut-layer as anetch stop layer. This 3D structure formation could include mix and matchbonding of various levels such as generic strata, semi-custom strata andfull custom strata. The memory strata could include a step of forming a3D NOR memory array and then bonding the memory control level to it.FIGS. 7E-7G illustrates such a process flow using a small section X-Z702 cut view.

FIG. 7E illustrates a small section of the memory control circuit 739(peripheral circuit). The section corresponds to the edge of two units.It illustrates four top bonding pin/pads 736,738 to be bonded to thememory pin/pads such as illustrated in FIG. 5E. It illustrates a feedthrough structure 735 and two bottom pin/pads 737 designated to beconnected to the logic level. The base could include base silicon 742and a cut-layer/etch-stop-layer 740. The bottom bonding pads could beplaced in the region between units which could be cleared of activecircuits. The bottom 737 pin/pads could be part of the first metal orthe contact layer. Alternatively leveraging the etch selectivity of thecut-layer 740 they could be formed even below it (not shown) to simplifythe later step of exposing them for preparing them as pin/pads. Otheroptions do exist including allocating more area for these pins/pads andusing a technique known as TSV. The structure includes top oxide 733 forprotection and will be part of the future hybrid bonding

FIG. 7F illustrates flipping and bonding the memory control circuit 744(from FIG. 7E) on top of memory strata 743. The memory strata 743 couldbe an array 752 of 3D NOR-P or any of the other memory optionspreviously discussed. Memory strata 743 could be formed over substrate756 with its own cut-layer (also could be called etch-stop-layer) 752.The feed-through 755 could be placed between the memory units. Thememory pin/pads 735,736, 738 from FIG. 7E could be connected to thecontrol level pin/pads 750 using hybrid bonding.

FIG. 7G illustrates the structure after thinning the memory controlcircuit 744 to form memory control 745 by techniques such as grindingand etch-back leveraging the etch-stop layer or any of the other cuttechniques previously presented herein or in the incorporatedreferences. The pin/pads 758, 760 are exposed or being formed by openingthe top via and forming the metallic top pin/pads using conventionalsemiconductor processes. FIG. 7G illustrates a small section of a fullmemory strata having the memory array and its control ready to be bondedon top of a logic wafer toward forming the type of structure illustratedin FIG. 7A. It could be expected that the number of connections from thememory control strata to the memory array 750 per unit could be fewthousands to provide the control to the word-lines, bit-lines and othermemory control lines. The number of feed-through 755, 758 per unit couldbe in the tens and so is the number of connections 760 to the processorlogic level, as previously discussed.

The memory controller could be integrated using bonding techniques or byother techniques such as common with 3D NAND with periphery under cell(“PUC).

The memory strata could be set to function as dual port memory such forexample one memory controller 714 is controlled by the underlyingprocessing logic while the upper controller 710 may be controlled by anoverlying processing circuit that could be part of the circuitsoperating to move data into the structure or out of the structure(“I/O”).

The memory strata could be set to function as a content addressablememory (CAM).

The stacking could utilize pin/pad connectivity as presented inreference to FIG. 5A-5E or other techniques such as smart alignment andelectronic alignment as was presented in the incorporated by referenceart, or any mix and match of these techniques.

FIG. 8 illustrates an exemplary overall process flow of designing thelogic wafer 802 and processing it 804. Design the customization of thememory wafer 822. There might be full set of generic wafers offeringmultiple process nodes and other memory option such as high density andhigh speed and so forth for the designer to choose from. The selectedgeneric memory wafer may then be customized 824 for the specific designand then flipped and bonded using, for example, hybrid bonding 828 tothe logic wafer.

The logic wafer and the generic wafer structure could include power lineconnections using the hybrid bonding as well. These power connectionscould be made at the unit level memory structure level and or die level.The figures do not show these power connections. The final processing inthis step may include back grinding, dicing and packaging.

The generic memory could be customized to support more than one level ofmemory using techniques presented in the incorporated by reference art.

The EDA tool for such a 3D logic-memory design could incorporatetechniques presented in at least U.S. Pat. No. 9,021,414, incorporatedherein by reference. For the flow presented in FIG. 8, the EDA toolcould include a grid for the memory decoder placement to support such aunit based generic memory fabric.

There are many options to form 3D systems using techniques such as beenpresented herein or in the incorporated by reference art. Thesetechniques could include adding pin/pads over the memory unit such as isillustrated in FIGS. 5A-5D. Such could include stacking a few memorylevels one on top of the other forming a 3D memory strata formed bystacking memory levels which could be 2D levels or 3D levels which couldbe a multilayer memory, for example, such as 3D NAND or 3D NOR and soforth. Such 3D structures could include sharing global memory controllines common between levels and independent layers or level selectsignal. Such memory 3D structures could be controlled by one or a fewmemory control layers controlling each of the memory layers using thecommon memory control pillars and the individual layer selects. Such 3Dstrata formation flow is presented in reference to FIG. 9A-9F herein.

FIG. 9A illustrates an X-Z 902 cut view of a small region of the memorycontrol strata similar to the one in FIG. 7E. The structure includes asubstrate 912 with etch-stop layer 910 and memory control circuits 909.The memory control circuits 909 structure could include ‘bottom’connections 904,907 in between units for future connection to theprocessor logic level, and feed-through 905. It also includes over thecontrol circuits the pins/pads 906, 908 for the ‘global pillars’ of thememory control lines. The global memory control connections do not looklike pillars as the keep folding over the top of the unit surface toaccommodate the relatively low pitch associated with the hybrid bonding.

FIG. 9B illustrates an X-Z 902 cut view of a small region of a 3D memory922 built over a substrate 926 with etch-stop ‘cut-layer’ 924. As well,the structure includes units feed-through 925 and over the unit bondingpins/pads 920.

FIG. 9C illustrates the structures after transferring the memorystructure 913 over the memory control structure of FIG. 9A and removingthe substrate 926 such as by grinding and wet and/or dry etch using theetch stop layer 924 for a controlled etch stop.

FIG. 9D illustrates the structures after adding in pins/pads 928 overthe 3D memory 922 units using a layout such as illustrated in FIG.5A-5E.

FIG. 9E illustrates an X-Z 902 cut view of an additional small region ofmemory 914 built over a substrate with an etch-stop ‘cut-layer’ inbetween the units' feed-through and over the units' bonding pins/pads.

FIG. 9F illustrates the structure after transferring the 3D memorystructure 914 over the structure of FIG. 9D, using hybrid bondingconnecting the respective memory control lines such as wordlines,bitlines and so forth, and connecting the feed-through. Accordingly thememory control circuits 909 could be used to control the overlayingmemory units of the first strata 922 and the overlaying memory strata914. The memory strata could be designed with the same memory unit sizeand the same number of memory control lines and utilize a standardpin/pads layout to enable such system level integration using hybridbonding. These memory strata could be 2D memory array or 3D memoryarray. They could be of very similar memory technology or in other casesdifferent memory technology. The memory control could be 2D structure ora 3D structure. Many variations of mix and match could be constructed.As was discussed before the use of global bitlines in a 3D structureneeds a control of the level select. Such level control needs to beproperly connected in the memory control circuits 909. There are fewoptions to do so such as:

A. Have an individual strata-select with direct connections to thememory control circuits. In such case the internal level select could beconnected to a global level select connected to the memory circuits.

B. Each memory strata could have dedicated connections for its levelselect. It is expected that the number of level selects could be couldbe less than 100 so allocating area for pin/pad for each of them wouldbe reasonable area overhead.

C. In a case that the objective is to stack the same type of memorystrata multiple times then a good choice would be to use the techniquepresented in respect to FIG. 22A-22B of PCT/US2017/052359, incorporatedherein by reference.

FIG. 9G illustrates the structure after removing the top substrate 913,adding pins/pads and repeating the flow by adding more memory strata934, 932, 930. So the structure could include a carrying substrate 942,memory control strata 940, first 3D memory strata 938 and stack of fourmemory stratum 930, 932, 934, 936. The structure of FIG. 9G could beused as a memory building block to be integrated with computing logicstrata to form a 3D computing structure.

One of the challenges for 3D system having multiple levels of activedevices is power delivery. The concept of heterogeneous integrationcould be extended to include substrate design to support power delivery.FIG. 10A, a vertical cut view 1002, illustrates a substrate similar tothe one illustrated in FIG. 7A with added global power deliverystructures. Such could include deep trenched capacitors 1016 and powerdistribution network (“PDN”) 1014. The deep trench capacitor can beformed inside a silicon wafer. In this case, the silicon substrate 1001would be heavily doped to form a bottom electrode of the trenchcapacitor as shown in FIG. 10A. Alternatively, the deep trench capacitorcan be formed within the oxide. In this case, a bottom electrode is canbe a metal liner (not drawn). The structure of capacitor can be one ofplanar type, crown type, pillar type, or cylinder type. In cylindertype, the top plate electrode can be heavily doped (such as phosphorousor boron doped) polysilicon or silicon germanium. One side of capacitorelectrode 1014A would connect ground/power line and another side ofcapacitor electrode 1014B would connect power/ground line. This could beformed using one thick metal layer, or multiple metal layers.Integrating trench capacitors in the PDN could be an effective way toreduce local voltage variation resulting from the circuits operation.FIG. 10B illustrates the structure after adding on the various levels oflogic, memory, EM interconnect levels, and IO level as was illustratedin FIG. 7A. Such could include hybrid bonding and multiple steps oflevel transfers.

Another embodiment of this invention is to integrate inductor for powerdelivery network. Such could include MEMS or CMOS-BEOL based inductor1017 can be an air, oxide, iron, or ferrite. When ferrite core is beingused, the core material can be manganese-zinc, nickel-zinc,iron-silicon, or iron-silicon-aluminum. A structure of the inductor canbe spiral type, thin film. One side of inductor electrode 1014A wouldconnect ground/power line and another side of inductor electrode 1014Bwould connect power/ground line as shown in FIG. 10C. The core materialof the inductor 1017, FIG. 10D illustrates the structure after adding onthe various levels of logic, memory, EM interconnect levels, and IOlevel as was illustrated in FIG. 7A. Such could include hybrid bondingand multiple steps of level transfers.

Another embodiment of this invention is to integrate both capacitorsshown in FIG. 10A and inductor shown in FIG. 10C simultaneously forpower delivery network

Level transfer and hybrid bonding may need special interconnect layerfor the formation of pad/pins as illustrated in FIG. 5A-5E. Forming suchstructure underneath the active circuit could require first to perform alevel transfer and substrate removal as is for example illustrated inFIG. 9B-9D. Wafer processing costs is highly dependent on the type ofprocess line used as is illustrated in the table of FIG. 11. The tableof FIG. 11 was published in April 2020 in a report titled “AI Chips:What They Are and Why They Matter, An AI Chips Reference”, Authored bySaif M. Khan, Alexander Mann, incorporated herein by reference. It showsorder of magnitude cost and price difference from 90 nm line to 5 nmprocess line. Accordingly it might be useful to construct specialcoupling level which could include electronic alignment capabilitiessimilar to those presented in reference to FIG. 1A-FIG. 3C, ofPCT/US2018/052332, incorporated herein by reference. Such coupling levelcould help building a heterogeneous integrated 3D system in which amemory level could in between unit bottom pins similar to 907 of FIG. 9Aand over the units top pads such as 906, 908. Using the coupling levelthe in between units pins 907 could be coupled to over the circuits padsstructure like the one illustrated in FIG. 5A, just using hybridbonding.

A 3D system like 700 could be constructed with all of the level beencustom made for that specific system or with many of the levels beinggeneric utilizing an agreed standard for pin/pads location and unitssize. Accordingly the coupling level could be made to comply with such3D heterogeneous integration standard. In some cases the over thecircuit pin/pads location could be part of a standard while thein-between units pin/pads or control line could be left custom to betterfit the specific memory or other type of circuit technology.

FIG. 12 is a section X-Z 1202 cut view of coupling level. Over aremovable substrate 1204 a switchable bottom pin/pad 1218 areconstructed following the concept presented in reference to FIG. 1A-FIG.3C, of PCT/US2018/052332. The transistor selection 1216 could be similarto the illustration FIG. 12B which is of FIG. 2E of PCT/US2018/052332.The selected signal, called there BL1-BL4, could be connected to overthe circuit pin/pad structure 1214, which could be formed according to astandard The coupling level could have a very simple control circuit1212 to perform the electronic alignment selection such as between GLSto GRS. The structure could include larger pin/pads for power supplyconnection, not shown. The control circuit 1212 could utilize twoconnected test pin/pads in the target level to measure connectivity andaccordingly select between which GLS to GRS. Additional larger pin/padcould be use to connect optional level select control pin. Such levelselect control signal could be used to disable both GLS and GRS. Suchlevel select could be useful for a case in which it is harder to formlevel select in the target wafer as presented in respect to DRAM asdiscussed in reference to FIG. 26A of U.S. Ser. No. 16/558,304,incorporated herein by reference.

While use of a coupling level with level select or the techniquediscussed in reference to at least FIG. 26A of U.S. patent applicationSer. No. 16/558,304 (U.S. Patent Publication 2020/0176420 A1) are analternative to level select within a memory level, it might be preferredto add the required additional process step for the memory level processin order to have level select within it. The type of level select couldbe engineered as part of the design of such M-Level. Such a design couldaccommodate single transistor types such as n-type and some relaxedselect transistor spec compensated by other element of the M-Level suchas design of the sense amplifier to support in memory level, levelselect as presented in reference to at least FIGS. 22C-22E of U.S.patent application Ser. No. 16/558,304 (U.S. Patent Publication2020/0176420 A1).

FIG. 12A illustrates the coupling level ready to be hybrid bonded to anover the circuit pin/pad structure. If the need is to bond to in-betweenpin/pad structure then a carrier wafer could be used to flip thestructure so it will bond first to in-between pin/pad structure.

The use of level transfer in 3D integration is often referred to asparallel device integration rather than sequential integration. Inparallel device integration, both wafers are processed separately(usually after transistor formation and some metallization) and thenafter, integrate them using a major process step, for example, such as,with hybrid bonding. This concept could be further extended to a methodto integrate a 3D system, for example, such as, in reference to FIG. 7Aherein. Such a 3D system may utilize more than one type of memory andmemory technology accordingly. The most common memory in computingsystems are SRAM or Ferro Electric memory being developed by FMC for theultra-fast memory such as cache, DRAM for the majority of the fastmemory such as main memory, and NAND flash for the high density memorysuch as data storage. Systems may include NOR type flash for the programcode storage and other types of memories such as cross-point memory,MRAM, or RRAM. In a 3D heterogeneous integrated system, these memoriescould be integrated by level transfer of a memory wafer processed in theproper wafer fab line utilizing the specific processing required forthat memory technology. The parallel integration process could be usedto accomplish the integration in phases. A First phase could beprocessing the needed wafers in the proper fab line which may includefront end of line processing (transistors) and back end of lineprocessing (interconnects). The Second phase could include leveltransfer to form a ‘master level’ or ‘memory level’, which could becalled the M-Level. Accordingly a memory control wafer (perhaps formedvia the first Phase) could be transferred on top of the memory wafer(perhaps formed via the first Phase, likely in a different fan line) toform an M-Level wafer. M-Level wafer may be stored whilst awaiting usein a 3D system. After the formation, and perhaps stockpiling of M-levelwafers, these M-Levels could be transferred and integrated to form adesired 3D system, as one example is illustrated in FIG. 13. The memorycontrol could comprise circuits (also known as ‘memory periphery’especially in 2D devices) such as decoders, sense amplifiers, chargepumps, self-test logic and similar memory control circuits. It couldinclude vertical connections to the memory level providing theword-lines, bit-lines, level select and so forth. The memory controlcould use hybrid bonding connection techniques such as been presented inreference to FIGS. 4A-4C, FIGS. 5A-5E and FIGS. 12A-12B herein, and FIG.21A to FIG. 27D of U.S. patent application Ser. No. 16/558,304,publication 2020/0176420, and FIG. 1A to FIG. 3C of PCT applicationPCT/US2018/52332, all incorporated in their entirety herein byreference.

FIG. 13A is an X-Z 1302 side view illustration of a wafer region. Itillustrates a phased integration of a 3D system. In the first phase,each of the wafers is processed in its respective process line such as alogic line for the processors level 1320, DRAM line for the fast memory1318, DRAM memory control 1316, 3D NAND line for the high density memory1314, and 3D NAND control logic circuits 1312. Alternatively, DRAMmemory control logic wafer 1316 can be processed from a logic fab whichis different from the DRAM line. Likewise, 3D NAND control logic wafer1312 can be processed from a logic fab which is different from the 3DNAND line. DRAM memory wafer 1318 may include only memory cells.Alternatively, DRAM memory wafer 1318 could include memory cells andsome core logic function such as sense amplifier and row/column decoder.3D NAND wafer 1314 may include only memory cells. Alternatively, 3D NANDwafer 1314 may include memory cells and some core logic function such assense amplifier, row/column decoders, and control line select gates. TheDRAM memory control logic circuit 1316 and 3D NAND control logic circuit1312 includes at least one of data buffer, address buffer, controlbuffer, mode resistor, error-correction control circuit, built-in test.

In the second phase, the M-Levels are formed by flip and bond (hybridbond) the DRAM control circuit 1316 over the DRAM circuit 1318 andsubstrate backside cut such as by using at least one of etching,grinding, or polishing the DRAM control substrate resulting in a bondedstructure 1324, and adding in the pin/pads level resulting in M-Levelfor the DRAM 1334. Similarly flip and bond the 3D NAND control circuit1312 over the 3D NAND circuit 1314 and substrate backside cut such as byusing at least one of etching, grinding, or polishing the 3D NANDcontrol substrate resulting in a bonded structure 1322 and adding in thepin/pads level resulting in M-Level for the DRAM 1332. Then in the thirdphase, the DRAM M-Level 1334 is flipped and bond over the processorlevel 1320, cut the DRAM substrate resulting in a bonded structure 1330,then add in as needed pin/pads structure and follow by flip and bond theNAND M-Level 1332 over the structure 1330, and cut the NAND substrateresulting in a bonded structure 1340.

The memory control signals such as data path, address, and commend linescould be shared between DRAM M-Level 1334 and 3D NAND M-Level 1332. TheDRAM M-Level 1334 and 3D NAND M-Level 1332 could have their owndedicated control signals.

FIG. 13B is an X-Z 1302 side view illustration of an alternative phasedintegration to form a 3D system. M-Level for the DRAM 1334 and M-Levelfor the 3D NAND 1332 may be processed separately and perhaps banked. TheDRAM M-Level 1334 and 3D NAND M-Level 1332 are flipped and bonded overthe processor level 1320 in, for example, a side by side arrangement(other arrangements are possible, touching edges, only touching onecorner, etc., all determined by engineering and manufacturingconsiderations), forming 3D system structure 1350.

It should be noted that the use of DRAM or 3D NAND herein isrepresentative of high speed/volatile memory or highdensity/non-volatile memory. As other memory technologies are becominguseful, for example, such as SRAM, cross-point memory, PCRAM, RRAM,FRAM, and MRAM, these memories could be integrated in a 3D System justas well as the presented concept.

As previously presented, a 3D system could be constructed utilizingindustry standards for unit size and pin/pad locations. The use ofstructures such as the M-Level could allow adhering to the standardwhile keeping flexibility for system architecture. Such could be theaggregating of multiple units in an M-Level for a specific applicationby that level control circuit.

Such a flow could have many variations including where within oneM-Level are included multiple memory levels first being bonded to formfirst a 3D memory structure such as presented in reference to at leastFIG. 21H, FIG. 25C, FIG. 25J, and FIG. 26A of U.S. patent applicationSer. No. 16/558,304, publication 2020/0176420, incorporated in itsentirety herein by reference.

With an M-Level integration the 3D system vertical connectivity per unitcould be scaled down to a bus format. Accordingly, the verticalconnectivity could include an address bus which could be decoded to theword-lines, bit-lines by the memory control circuits of each M-Level.The system level vertical connectivity per unit could count about ahundred lines rather than thousands of lines. The feed through conceptsuch as feed-through per units 718 of FIG. 7B herein could be used forsuch vertical per unit bus. The vertical lines or pillars could beallocated, for example, to 32 data, 34 Addresses, 4 system types, 16controls, and 14 feed-throughs. Specific systems could use more or lessthan 100 pillars lines bus per unit. Such vertical busses could utilizetechniques common in the industry for computer system busses, such asmultiplexing data or address lines or use of an industry standard suchas AMBA, Avalon and so forth. A range of industry On-Chip bus standardsare reviewed in a paper by Mitić, Milica, and Mile Stojčev. “An overviewof on-chip buses.” Facta universitatis-series: Electronics andEnergetics 19.3 (2006): 405-428, incorporated in its entirety herein byreference.

FIGS. 14A-14B are vertical X-Z 1402 cut view illustrations of a regionof such 3D system, at different scaling factors. FIG. 14A shows fewunits 1406 and the vertical bus 1408 in-between. The 3D system could beconstructed over a functional substrate 1403 including a heat removalstructure, trench capacitors or integrated inductors, and powerdistribution network(s) as previously discussed and a stack ofheterogeneous integration of levels and M-levels 1404 as previouslydiscussed. In addition to the vertical data bus the system could includea power bus to support distribution of power to the various levels. Thevertical power bus could be in the same unit side or at the otherssides. Other vertical common pillars could be used, for example, such asa common clock, and test signals. The unit side size could be 200 μm asoften referenced herein or other sizes including different sizes both inX direction and in Y direction, for example, such as about 0.1 mm. about0.2-0.4 mm. about 0.4-0.8 mm, about 0.8-1.2 mm, about 1.2-1.6 mm, about1.6-2.2 mm, about 2.2-3.5 or even larger than about 3.5 mm.

FIG. 14A illustrates the use of redundancy for the vertical pillars 1414for such bus common vertical connectivity. FIG. 14B shows that threevertical pillars 1414 are carrying the same signal of the vertical busand are wired together to common horizontal signal 1416 fed into theM-level to be used. The M-level control circuit could include decodersand other control circuits including bus de-multiplexing, level select,power generation including voltage pumps circuits and other circuitssuch as often called memory periphery circuits.

FIG. 14B illustrates a portion of a 3D system having a functionalsubstrate 1411, a processors level 1420, a high speed M-level 1422, ahigh density memory M-level 1424, horizontal electromagneticinterconnect M-level 1426, and input output M-level 1428 to connect the3D system to external devices. The 3D system could also include athermal isolation layer 1421 to isolate the processor heat from theoverlaying memory level, and shielding layer 1425 to protect theunderlying levels from the EMI noise that could be associated with theelectromagnetic interconnect M-level 1426.

The 3D system of FIG. 14A-14B could include coupling level(s) such aspreviously discussed or a coupling level to interface the industrystandard used in the system to a level or M-level built for otherstandards. Such a coupling level could be considered as standard tostandard coupling level.

FIG. 14C is a horizontal cut X-Y 1432 illustration of a region of a 3Dsystem, showing a sub array of 6×3 units 1438 with their associated sidevertical pillars of bus lines 1434 and 1436; these could include theirredundancies pillars. While FIG. 14C illustrates the vertical buspillars 1434, 1436 as blocking the gap between units it could beexpected that the design of such 3D system could be made to supportconnectivity X-Y connectivity between adjacent units and across units(not shown). These designs could be made by engineers in the art toaccommodate the tradeoffs associated with the vertical pillars, pin/padsdesign rules and number of vertical pillars and their redundancies,units size and other system considerations and design rules.

Additional alternative to accommodate bonding misalignment while stillusing hybrid bonding could be the technique presented in reference to atleast FIGS. 93A-94C of U.S. Pat. No. 8,395,191, incorporated in itsentirety herein by reference.

An additional advantage of the use of M-level concept is forpre-testing. In reference to at least FIG. 86C of U.S. Pat. No.8,395,191, incorporated in its entirety herein by reference, a conceptof contact-less or wireless testing has been presented. Such could beused to perform testing of an M-level designated to be integrated to a3D system. Probe test or other form of tests including use of self-testand scan based testing could be used to test a level and mark any unitthat has a fault that could not be overcome by the unit levelredundancy. Such pretesting could be an important part of 3D systemintegration to enable overall system yield. Furthermore, M-Level mayinclude post-package repair function by containing redundancy rows andcolumns of memory cells, address map/re-map blocks, built-in test,anti-fuse. M-Level may even further include soft-post package repaircircuit. In addition, M-Level may also include on-chip error-correctioncircuits.

In such manufacturing operation there are multiple advantages andoperational alternative options following such levels and M-level testsprior to performing the 3D integration using, for example, such ashybrid bonding. One option is to select high yield levels and M-levelsfor 3D integration while lower yielding levels could be used for otherapplications such as standard memory products or other standardfunctions. The lower yielding level could be integrated also in 3Dtechniques to a structure with fewer levels in which such yield losscould be acceptable or repaired. Another option is to performingmatching of levels to maximize the 3D system yield by matching levelsfor minimal yield loss by aligning the faults so as many faulty unitsare overlaying other faulty units. The unit based 3D system architect inwhich each units has its own vertical connectivity and power deliverycould be used to support functional overall system even if some of theunits do have faults and should be disabled. This could be considered asa redundancy or agile system reconfiguration. So using test such as scanbased or other types of Build In Test (“BIST”) the system disables unitsthat could not be repaired with their built-in redundancy.

FIG. 14E vertical X-Z 1442 cut view illustrations of a region of analternative 3D system 1450 which includes a mixed ‘grain’ M-level 1444and functional substrate 1443. In such alternative the upper region ofan M-level could have courser unit partitions 1448 than the lower levelpartitions 1446. The upper M-Level could include a level or levels whichincludes high density memory, for example, such as, 3D NAND type memory.Such memory is associated with far longer access times and could supportthe system performance with reduced vertical connectivity. Othervariation of the 3D system modularity could be useful in someapplications.

An additional option with the 3D system is illustrated in FIG. 14E is tomove the process rather than the data, namely a memory centricarchitecture. For years the common practice has been to bring the datato the processor to compute a required instruction. As the amount ofdata keep growing, an alternative approach could be more efficient andit is to bring the processing units to the data. In a 3D system aspresented herein, a massive amount of data could be stored in the 3Dsystem, forming pooled memory. As an example, the data related to theU.S. (United States) could be stored in locations marked by US data(bubble) 1452 and data related to Europe could be stored in locationsmarked by Europe data (bubble) 1453. So if a search or other operationis to be done to U.S. data, the proper program could be transferred tothe processors close to the U.S. data, marked by close processors(bubble) 1454. In some systems the processor could include programmablelogic such as FPGA gates and related structure of programmable logic.Accordingly, the proper bit-stream to program the configurable logiccould be transferred to the close processors (bubble) 1454 in proximityto the data designated for the processors 1452. Another variation ofthis concept could be for solving a problem in which a massive amount ofdata is required to be processed and then followed to a follow-onprocess such as in deep neural network. In such case it might be moreefficient to store the processed data near to the original data (bubble)1452 and move in a new program to the close by processors (bubble) 1454for the next processing step. Thus, processing energy will besignificantly lower due to the close proximity of data and processor,and the raw performance will be greater.

The 3D system as has been presented herein in reference to FIG. 13A toFIG. 14E is about various heterogeneous constructions of a modular 3Dsystem. The M-Levels may have very high connectivity between the memorycontrol level and the memory level with hundreds or thousands ofvertical connections per unit for the bit-lines and the word-lines, andadditional control as needed for example, such as, level select. Suchvertical connectivity could utilize hybrid bonding and pin/padsstructure(s) similar to the one presented herein in reference to FIGS.5A-5E, or such as has been presented in reference to at least FIG. 21H,FIG. 25C, FIG. 25J, and FIG. 26A of U.S. patent application Ser. No.16/558,304, publication 2020/0176420, incorporated in its entiretyherein by reference. It could also use techniques such as beenreferenced herein, such as, for example, as electronic alignment. Itcould also use other techniques such as been reference as smartalignment in the incorporated by reference art. Such rich vertical perunit connectivity could be used within the M-Levels, while at the 3Dsystem far more relaxed vertical connectivity could be used leveragingthe vertical bus per unit concept—reference, for example, FIG. 14A-14Cherein. Accordingly each level in the 3D system could support thevertical connectivity of the bus per unit. Some levels could support itas a feed-through and others also via a connectivity bus or bussesbetween levels in the system. Reference to FIG. 7G the vertical bussignal 758 is illustrated as feeding the memory control 739 of theM-Level and also as feeding through 755 to the memory level 752. Aspreviously discussed, the design of a memory level could include thedesign of the feed-through pillars to support the connectivity of thevertical per unit system bus. Accordingly the 3D system could includemoderate vertical connectivity per unit such as about hundred pillarsper unit bus and rich connectivity within the M-Levels such as athousand pillars per unit to support the connections between the memorycontrol level and the memory array of the word-lines and bit-lines 753.Different vertical connectivity techniques and alignments techniquescould be used for the vertical busses and the per M-Level internalvertical connectivity.

In some 3D systems the vertical connectivity could include more than onevertical bus per unit. These vertical buses could have differentfunctions, for example, such as one vertical bus connecting memoryM-Levels to the processors level which could be called M-bus. And anadditional vertical bus connecting the X-Y connectivity M-Level to theprocessor level which could be called C-Bus. For example, the M-bus insome systems might not even be extended to the X-Y connectivity M-Level,and the C-bus in some systems might not just feed through the memoryM-Level. The C-bus could be similar to the M-bus or very different, forexample, such as utilizing different industry bus standards and soforth. The bus per function could be extended to a bus for high speedmemory which could be called SM-bus and a bus for high density memorywhich could be called DM-bus. The SM-bus could be designed for highspeeds, for example, such as using a wide data bus of more than 16pillars for data while the DM-bus could be designed for high integritywith, for example, built-in redundancy and error correction features.

In some systems the unit could have subunits such as been illustrated inFIG. 14D, an X-Y 1442 cut view illustration of an example of a unit 1430with sub-unit for communication processor 1432 and 16 sub-units 1436 ofAI processors. The communication processor 1432 could have a C-bus 1434for communicating with the X-Y connectivity M-Level, and a M-bus toconnect it to its overlaying memory. The AI processors 1436 could havean M-bus to connect it to its overlaying memory. Additionally theprocessors level could have a horizontal bus (not shown) connecting theAI processors to the communication processor 1432. The sub units 1436could have a side size of 100 μm or other sizes as was referenced hereinpreviously for unit size. The system could include a mix of differenttypes of units optimized for the different type of tasks. Many othervariations of these concepts could be designed by an engineer in the artto construct a 3D system capable of efficient parallel processing andalso serial processing with across-the-system effective connectivity.

An additional alternative is to extend the M-bus to far larger number ofdata pillars, for example, such as 80, 160 or even more than 320. Suchextended M-bus increase the data communication between the processinglevel and the memory level for supporting an increase in overallprocessing speed/performance.

With an extra wide data bus and units level partition of the memoryarray, a memory level based on 3D NAND technology could provide areasonable data rate to serve in the role of high speed memory for thesystem. Such 3D NAND technology could be modified to utilize extremethin tunneling oxide, thereby giving up retention time to gain fasterwrite and erase time and far better endurance as discussed in at leastU.S. Pat. No. 10,515,981 and PCT application PCT/US2018/016759,incorporated herein by reference. Modifying 3D NAND technology forUltra-Low Latency memory is been practiced in the industry by Samsungwith their product line called Z-NAND. Such a concept could be furtherenhanced by use of extremely thin tunneling oxide, a very wide data bus,and partition of the memory array to hundreds of units leveragingstacking of memory control over the 3D NAND memory arrays as has beenpresented herein and in some of the incorporated references.

In general, the 3D system presented herein could resemble prior systemswhich used to connect chips and packages employing Printed Circuit Board(“PCB”). Many of the system architectures of those PCB integratedsystems could be mapped to the vertical 3D system presented herein.

The M-Level concept could be extended beyond memory to other functionalelements of the 3D system. Such could be the X-Y interconnect usingelectromagnetic waves. Connectivity M-Level could include a controllevel, modulation and decoding level and the transmissionlines/waveguides levels. So the bus vertical connectivity could be usedby the X-Y interconnect controller which could then propagate theinformation to the X connectivity channels and the Y connectivitychannels.

Wafer scale 3D systems as presented herein would likely need redundancyand yield repair or yield agility to become a commercially viabletechnology. Such has been presented herein and in the incorporated byreference art including multiple techniques such as in reference toFIGS. 35A-35C, FIGS. 38A-38C of U.S. patent application Ser. No.16/558,304 (publication 2020/0176420), incorporated herein by reference.Additional 3D based redundancy and repair technology has been presentedin reference to FIG. 17 and FIG. 24A to FIG. 44B of U.S. Pat. No.8,994,404, incorporated herein by reference. Each M-Level in the 3Dsystem could include its own self-test and repair technology, as isknown in the art for memory and mission critical circuits. Additionaltechniques for 3D systems could include adding redundancy M-Level suchas a second back up level for the X-Y connectivity M-Level. Or adding aredundancy vertical bus per unit. These redundancy levels could beconnected in so they are used to enhance the system and provide faulttolerance, agility for defects, and graceful ageing.

The 3D system as presented herein is utilizing many units which haveprocessor memory and able to interconnect utilizing X-Y connectivitylevel. Such systems are sometimes referred to as a ‘network on chip’(NoC). Such a system could manage defects by either calling spare unitsto be activated to replace defective units or provide an advance taskallocation capability to distribute the work load to the available goodoperational units. Concepts for such complex systems with self-repairand operational agility are well known in the art and are in use such aswith server farms and other multi computer systems. Such technologiescould include use of a circuit known as a “watch dog” in which goodoperational units would periodically trigger the watch dog circuitannouncing that the unit is in good operational condition. If the watchdog is left too long without such trigger, it could activate a unit failsafe mode. Therefore, once a failed unit is detected, the watch dogcircuit could activate a controlled vertical bus disconnect to isolatethe failed processor from the vertical bus to avoid the failed unit fromaffecting the operation of other units of the 3D system. In such asituation the circuit could also initiate a processor reboot to overcometemporary faults and revive unit operation. If the fault is permanentthen in addition to bus isolation the watch dog circuit could controlthe processor central operating clock circuit to further reduce thedamage of the faulty unit processor and reduce its power consumption. Inaddition the 3D system could include system procedures in withperiodically each of the unit is been ping by the 3D system taskallocator processor. And if a unit is deemed faulty by the taskallocator processor then a recovery operation could be activated toassign a spare unit to replace the faulty unit. Alternatively the 3DSystem could include agility to reallocate the system task between theoperating units. An artisan in the art of large scale multi computerssystem could design such built-in test, detection, and recoverytechnology into the design of the 3D system.

Another alternative for such 3D systems is to have levels constructed bymultiple die transfer instead of one wafer transfer as been presented inreference to FIG. 43A-43E of U.S. patent application Ser. No.16/558,304, publication 2020/0176420, incorporated herein by reference.Such die level transfer could also utilize a technique called‘Collective Die to Wafer Direct Bonding’ as presented in a paper byInoue, Fumihiro, et al., “Advanced Dicing Technologies for Combinationof Wafer to Wafer and Collective Die to Wafer Direct Bonding.” 2019 IEEE69th Electronic Components and Technology Conference (ECTC). IEEE, 2019;also by Nick Flaherty titled “Collective die-to-wafer bonding with sub-2μm accuracy for 3D packaging” ee News Europe, Oct. 19, 2020; and byBrandstätter, Birgit, et al. “High-speed ultra-accurate direct C2Wbonding ” 2020 IEEE 70th Electronic Components and Technology Conference(ECTC). IEEE, 2020; all of the forgoing are incorporated in theirentireties herein by reference. Such a die level transfer could utilizethe M-Level concept to have the die transfer to a base level forming anM-Level which could be called DieM-Level and then transferred togetheronto the 3D system stack.

Such DieM-Level concept could be used for an X-Y connectivity M Levelutilizing lasers, photodetectors, and waveguides as was presented inreference to at least FIG. 35A to FIG. 37B of U.S. patent applicationSer. No. 16/558,304, publication 2020/0176420, incorporated herein byreference. Such DieM-Level may be implemented by silicon photonics whichincludes the photodetectors made by silicon-germanium alloy. Thewavelength of the photonic connectivity may be about 1.3 um or about 1.5um, but other useful wavelengths may be possible. Such DieM-Level couldbe part of a 3D system such as reference numeral 1447 of FIG. 14Eherein. An example is presented in reference to FIG. 15A-15D hereinwhich are X-Z 1502 cut view illustrations.

FIG. 15A illustrates a drive and control wafer 1504 having waveguides1512 disposed over control and drive circuits 1514 over a cut-layer suchas SiGe 1516 over a substrate 1518. The drive and control wafer 1504could include connection pads 1506 for connecting the drive and controlwafer 1504 to one or more laser diodes die 1520, which could be bondedon top, and transparent via 1508 to guide the laser beam to the beamsplitter and direction change assembly 1510 and thus guide the laserbeam(s) to the appropriate waveguides. Techniques for processing suchwaveguides and optical interconnect structures are known in the art suchas been presented in U.S. Pat. Nos. 5,485,021, 5,987,196, 6,791,675,7,203,387, 8,548,288, 9,197,804; and in a paper by Lo, Shih-Shou,Mou-Sian Wang, and Chii-Chang Chen. “Semiconductor hollow opticalwaveguides formed by omni-directional reflectors.” Optics Express 12.26(2004): 6589-6593, all of the forgoing are incorporated herein byreference. The laser diodes die 1520 could also be built on a substrate1530 with optional cut-layer 1528. The laser diodes die 1520 couldinclude many diodes each with its pin/pad connection in transparent viasoutput and support structures such as ground/power connections. Thelaser diodes could be built on crystal 1526 that is a good fit for lasergeneration for example, such as GaAs, InP, GaSb, GaN, etc. The crystallayer 1526 may be different material from the substrate 1530. Forexample, the crystal laser 1526 may be a crystalline direct bandgapsemiconductor grown on a silicon substrate 1530 through a buffer layer.Alternatively, a piece of crystalline direct bandgap semiconductor thatso-called die is transferred and bonded onto a silicon substrate 1530.The laser diodes die could include pin 1522 and transparent via 1524. Inmany cases the crystals used for laser diodes are not available on 300mm wafer and accordingly die level transfer could be preferred for 3Dintegration applications.

FIG. 15B illustrates the bonding of a few laser diodes die 1520 on topof a drive and control wafer 1504.

FIG. 15C illustrates the bonded structure 1540 after thinning thesubstrate of the laser diodes dies 1520. If the laser diode dies 1520are built with a cut-layer built-in then such a cut layer, for examplecut-layer 1528 shown in FIG. 15A, could be used for this thinning step.Many of the crystals used for laser diodes are built using epitaxialgrowth on top of another crystal. Such a process could be used to forman etch stop cut-layer between the carrying substrate and the diodelaser crystal. Following the thinning process other process steps couldbe used, for example, such as conformal oxide deposition, for fillingthe gaps between the laser diodes dies and then CMP to provideplanarization If needed, then steps to form connections pin/pads on nowthe top surface could be utilized.

FIG. 15D illustrated the structure of FIG. 15C after it was flipped overanother substrate 1548 with cut layer 1546 and having its substrate 1538removed. The structure of FIG. 15D could be made ready as a DieM-Levelby adding the pads/pins for the C-bus future vertical connection (notshown).

The thinning of the dies substrate after they have been bonded to thetarget wafer as is illustrated in the step between FIG. 15B to FIG. 15Ccould be accomplished with grinding and wet-chemical/plasma etch back.For silicon based dies, a SiGe based cut-layer could enable extremethinning to even below 500 nm final thickness. In some cases thethinning of the dies substrate could use other forms of etch stop orcould be done to less extremes such as to 20 or 10 μm level without theuse of a cut layer. This would be engineered to determine the optimumprocess for the particular product and structure needs. Much of theseengineering tradeoffs and possibilities have been discussed in variousconstituents of the incorporated by reference references.

An additional consideration of such a 3D system is heat removal from theupper levels, for example, such as, the stack of heterogeneousintegration of levels and M-levels 1404 of FIG. 14A herein. U.S. Pat.No. 8,674,470 incorporated in its entirety herein by reference, teachesthe use of the power lines to provide heat removal paths from a level ina 3D structure to the bottom most or top most surface where the heatcould be removed by air or fluid conduction. This could be an additionalfunction of the per unit vertical pillars such as those used for thevertical bus. These pillars, for example, such as vertical pillars 1414of FIG. 14B, could be designed to provide good conductivity of power tothe specific level and also to remove the heat out of levels that couldneed heat removal. These heat removal pillars could be considered as‘thermal vias’. These pillars could be designed to have a good thermalpath to the cooling substrate 1401 of FIG. 14A herein, while beingelectrically isolative. Methods of forming and utilizing a thermallyconductive contact while being electrically non-conductive, for example,such as presented in reference to at least FIG. 6 of U.S. Pat. No.8,674,470. And in a similar way these pillars could be thermallyconnected and electrically isolated up to and including the top levelwhich could include the heat sink structure for heat removal by air orfluid conduction. In one embodiment, those via may be designed in a wayto mitigate or even shield electromagnetic interference.

Moreover, thermal isolation techniques, methods, materials andstructures such as disclosed in the entirety of U.S. Pat. No. 9,023,688could be utilized in the 3D systems and devices disclosed herein. Theforgoing U.S. patent and its entire contents are incorporated herein byreference.

FIG. 16A illustrates a side X-Z 1602 cut view of a 3D system similar tothe one disclosed in FIG. 14E herein including an upper level 1604 ofcomputing logic. A thermal isolation layer 1605 could be used to keepthe heat of the computing logic 1604 from substantially reaching memorystack 1603 disposed underneath, and a heat-sink 1606 could be used toremove the heat out of and off the device/system. The normallyconductive power lines (not shown) could be, in part, thermallyconnected and electrically isolated with respect to heat sink 1606 tohelp remove the formation and operational heat produced by internalstack 1603 from the top, in addition to heat removal thru to the bottomsubstrate 1601 with its liquid micro channel cooling 1610.

FIG. 16B illustrates a similar 3D system in which the upper level ofcompute logic has its own liquid cooling substrate 1614, which couldinclude power delivery lines and trench capacitors in a similar manneras to the bottom substrate 1601. The liquid cooling substrate 1614 couldbe a part of silicon interposer, or separately fabricated and bondedinto the 3D system, or even monolithically integrated with the base dieof the silicon substrate of 3D system.

The motivation for hyper-scale integration could suggest adding morecompute levels to a 3D system. Yet such compute levels could generatetoo much heat to be removed just by the power line network. It might bedesired to embed levels with liquid micro-channel cooling inside the 3Dstack and not just at the bottom and top as is illustrated in FIG. 16B.The micro-channel cooling can be fluidic channel of a coolant or heatpipe. These micro-channels could further be coupled with conventionalpassive cooling such as finned heat sink and ventilation slots. In oneembodiment of this invention, a micro-channel can include forcedconvention device such as fans and nozzles. The coolant can be pumpedloops of heat exchangers and cold plate outside of the 3D system.

The challenge is to manage the system vertical (Z direction)connectivity through a thick substrate which could support micro-channelcooling, such as presented by Colgan, Evan G., et al. “A practicalimplementation of silicon microchannel coolers for high power chips.”IEEE Transactions on Components and Packaging Technologies 30.2 (2007):218-225, incorporated herein by reference. Such substrate could be atleast 50 μm thick and could require TSVs through it having diameters ofabout 5 μm. The pillars used for the vertical bus could use a throughlayer via, also called nano-TSV, with diameters of less than 1 μm. Oneapproach to manage such vertical connectivity challenge could be tomodulate the signal through the TSV such as by using RF interconnects oroptical interconnects similar to what have been presented for the X-Yconnectivity herein.

FIG. 16C illustrates a side X-Z 1602 cut view of a 3D system withembedded micro-channel cooling substrate 1624. The substrate couldinclude TSVs 1622 which could be used for power line connectivitythrough the substrate and electromagnetic wave carrying modulated data.The layer below 1623 and the level above 1626 could include the circuitsto control, generate, and detect the electromagnetic modulated datatravelling through the TSVs 1622. The top level could include additionalX-Y electromagnetic connectivity 1628 or connectivity to an externaldevice which could support wireless connectivity.

For optical types of electromagnetic modulation, the via could be madeoptically transparent either by proper oxide filling or left unfilled.Similar optical via connectivity has been presented in U.S. Pat. No.7,203,387, incorporated herein by reference.

For RF type of electromagnetic modulation the via could be copper filledor a Coax-like TSV transmission line using conformal side wall fillingouter shell of metal, then an inner oxide, and then metal again. Thisstructure could be accomplished by using ALD or other types of conformaldeposition. RF-type TSVs are known in the art, for example, such aspresented in U.S. Pat. Nos. 8,618,629, 8,759,950, 8,916,471, and in apaper by Bleiker, Simon J., et al., “High-aspect-ratio through siliconvias for high-frequency application fabricated by magnetic assembly ofgold-coated nickel wires.” IEEE Transactions on Components, Packagingand Manufacturing technology 5.1 (2014): 21-27; by Vitale, Wolfgang A.,et al., “Fine pitch 3D-TSV based high frequency components for RF MEMSapplications.” 2015 IEEE 65th Electronic Components and TechnologyConference (ECTC). IEEE, 2015; by Ebefors, Thorbjörn, et al., “Thedevelopment and evaluation of RF TSV for 3D IPD applications.” 2013 IEEEInternational 3D Systems Integration Conference (3DIC). IEEE, 2013; theentirety of all of the forgoing patents and papers are incorporatedherein by reference.

Another option is to build special M-Levels designed for a coolingsubstrate to be inserted inside the 3D stack. Such a SubstrateM-Levelcould utilize conventional TSVs with a redistribution layer connectingthese large TSVs to relatively smaller TSVs used in-between units forthe per unit vertical bus. For a unit sized about 200 μm×200 μm, thearea for 100 large TSVs 5 μm×5 μm could be about

100×5/200×5/200= 1/16 of the unit area leaving room for the microchannels and the trench capacitor.

FIG. 16D illustrates a side X-Z 1602 cut view of a cooling substrate1644 with TSVs 1646, and logic level 1634 with re-distribution layersand pads 1636 for the TSVs and in-between units pins for the verticalbus 1632 (two are shown).

FIG. 16E illustrates a side X-Z 1698 cut view of a SubstrateM-Level 1650formed by adding top redistribution layer 1654 to the hybrid bondedstructure of FIG. 16D. The per unit vertical bus pin/pads 1632, 1652 areconnecting the vertical bus using the TSV 1646 through the coolingsubstrate. The cut layer 1656 could be used to separate theSubstrateM-Level from the carrying substrate 1658.

Using such a SubstrateM-Level a 3D system could include multiple computelevels and memory levels with X-Y connectivity levels in-between, whilethe system heat could be managed by liquid cooling.

For multiple level 3D systems it could be desired to add a logic levelthat could be optimized for data movement rather than data processing,for example, such as we have seen in the past with an Intel 8237, adirect memory access (DMA) controller, as part of the MCS 85microprocessor system. Such a 3D system, as is illustrated in FIG. 16C,could include a base of water cooled processors level(s), overlaid by ahigh speed memory M Level, overlaid by high density memory M Level,overlaid by dedicated data movement M Level, overlaid by an X-Yconnectivity M Level, overlaid by a high density memory M Level,overlaid by a high speed memory M Level, overlaid by an additional watercooled processor M Level, overlaid by a device to external systemconnectivity M Level. A heat spreader layer could be used to average theheat between the various units to reduce the local heat spots. A phasechange material layer could be used to average the heat over time toreduce the momentarily heat peaks. And active heat management could beused by integrating per zone, for example, such as per unit temperaturesensors integrated with temperature control circuits. Such temperaturecontrol circuits could also control the unit processor operations toprevent overheating. Such could be done by slowing down the processorclock or reducing the processor power voltage or affect the periodicquiet time, or activate a shut down. These active techniques manage theoperating speed to avoid overheating. The outlined 3D system integrationreduces the overall interconnects of the system and accordingly allows afar more power efficient and speed efficient computing system. Yet,power budgets and heat budgets provide limits to the 3D systemoperation. These heat management techniques allow optimized operationwithin such overall heat budget.

Another alternative is to include use of multiple steps of simplebonding and thinning, and then using TSV processing to form the verticalbus pillars through the levels-stack and then form the pin/pads for thefull M-Level for the following steps of hybrid bonding integration. Sucha flow is presented with the use of FIGS. 17A-17D. The advantage forsuch a flow is the saving of pin/pads formation for the inner levels ofsuch a levels-stack.

FIG. 17A illustrates a side X-Z 1702 cut view of a base level 1706 andan inner level 1704. Each of these levels is structured as spaced units1724 and in-between connections 1722 which could be used for laterconnection to the vertical bus pillar 1726. FIG. 17A also shows the twolevels being bonded to each other creating structure 1708, in which theinner level 1704 has been flipped and bonded to the base level 1706.

FIG. 17B illustrates the structure after removal, ‘cut’ of the innerlevel 1704 carrying substrate 1705.

FIG. 17C illustrates the structure after repeating the process five moretimes forming a level-stack of base level and six inner levels bondedon-top.

FIG. 17D illustrates the structure after forming a through stack via(TSV) 1726 and bonding pin/pad 1724. The inner level thickness could beabout 100 nm or larger such as about 0.5 μm, about 1 μm, about 2 μm,about 4 μm or even more than 6 μm. The through stack via (TSV) 1726(through the level-stack) could go through few tens of microns which iscommon for TSVs in the industry. The metal filling of the via could formsimultaneously the connection to the horizontal between the unitsconnection lines 1722. Such is not common and would need proper tuningof the process by an artisan in semiconductor processing. It reasonableto expect that such a through stack via would require larger spacebetween units 1730 than what would have been required if the via wouldbe formed for each level independently thus increasing the structuresizer, and yet the simplicity of the process could make it attractive insome applications. The industry is improving the etch technology forsuch vias and an aspect ratio of 1:20 has been demonstrated. Thus, for alevel-stack of 20 μm thickness a via of about 1 μm diameter could bemanufacturable.

In some 3D systems, for example, such as mobile systems, alternative(not liquid cooling unless recycled) heat management techniques could beused.

The 3D system as presented herein could be of a full wafer or diced to asub-wafer size. Such dicing could be done in regular patterns which maybe designed to match the yield to maximize the good yield structures outof the multi-level wafer structure. Such dicing could be done by many ofthe dicing techniques used in the industry. A more advanced dicingtechnique such as use of plasma etching could be effective and allowflexible dicing patterns as well as reducing the size of the dicinglanes (often called streets). The dicing or singulation pattern coulduse a mask pattern or mask-less patterns for even greater flexibility,especially when employing directional etching/matter removal techniques,for example, such as plasma based etching.

In general the construction of a 3D system as presented herein includesmultiple steps of layer transfer. Such layer transfer could includeflipping over a donor wafer on top of a target wafer and performinghybrid bonding. Then grind and etch back the donor wafer substrateleveraging a built-in cut layer, for example, such as SiGe. And ifneeded forming pins/pads for the next step. These steps could include anexchange role of donor wafer or target wafer and removing substrate fromeither or both as presented in reference to at least FIG. 13A herein andwithin many incorporated references. These steps of layer transfer couldinclude use of a carrier wafer as presented multiple times in theincorporated by reference art or as presented in a paper by Jourdain,Anne, et al., “Extreme wafer thinning and nano-TSV processing for 3Dheterogeneous integration.” 2020 IEEE 70th Electronic Components andTechnology Conference (ECTC). IEEE, 2020, incorporated in its entiretyby reference. The use of a carrier wafer helps performing the back sideadds of pin/pads on a side wafer rather than on the target 3D structure.Additionally it effectively flips back the transferred layer to bealigned to the target wafer in a non-flipped form. So, for example, inreference to FIG. 13A herein, the structure 1318 would have been acarrier wafer than the flow formation to the structure 1330 could berepresentative of a carrier wafer use prior to the final step of removalof the carrier wafer. The carrier wafer removal process/method could besimilar to the removal of a substrate by using grind and etch back toa(n) (built-in) etch stop layer.

A 3D system presented herein could be considered as a semiconductordevice and be integrated into a larger system using other integrationtechnologies used in the industry such as Printed Circuit Board (PCB),interposers, substrates and integration techniques also known as 2.5D,as well as others.

It will also be appreciated by persons of ordinary skill in the art thatthe invention is not limited to what has been particularly shown anddescribed hereinabove. For example, the use of SiGe as the designatedsacrificial layer or etch stop layer could be replaced by compatiblematerial or combination of other material including additive materialsto SiGe such as carbon or various doping materials such as boron orother variations. And for example, drawings or illustrations may notshow n or p wells for clarity in illustration. Further, any transferredlayer or donor substrate or wafer preparation illustrated or discussedherein may include one or more undoped regions or layers ofsemiconductor material. Further, transferred layer or layers may haveregions of STI or other transistor elements within it or on it whentransferred. And for example the order of the levels and their functioncould be different from what have been illustrated here, the use ofhybrid bonding or other type of bonding and the relevant alignmenttechniques and their vertical connectivity could be mix and matchedusing techniques presented herein or in the incorporated by referenceart or elsewhere. Additionally the modular approach of a typical unitbased architecture could support a desired flexible system constructionsuch as dicing the 3D heterogeneous integrated wafer to a size of 40×40mm2 system or too far larger sizes such as 100×100 mm2 system or evenusing the 3D wafer as a final system. Also the system could be designedwith a mix of units having different sizes and/or differentfunctionality including units to support AI calculation and units tosupport data management and system management. Furthermore, the 3Dsystem could be extended beyond wafer sizes by utilizing panels withbuilt-in wave guides or transmission lines as presented in respect toFIG. 43A to FIG. 43E of U.S. patent application Ser. No. 16/558,304,publication 2020/0176420, incorporated herein by reference.

There many options and engineering consideration to construct specificsystems utilizing the techniques presented herein as those in the artcould apply. Rather, the scope of the invention includes combinationsand sub-combinations of the various features described hereinabove aswell as modifications and variations which would occur to such skilledpersons upon reading the foregoing description. Thus, the invention isto be limited only by the appended claims.

We claim:
 1. A 3D device, said device comprising: a first levelcomprising first transistors, said first level comprising a firstinterconnect; a second level comprising second transistors, said secondlevel overlaying said first level; a third level comprising thirdtransistors, said third level overlaying said second level; a pluralityof electronic circuit units (ECUs), wherein each of said plurality ofECUs comprises a first circuit, said first circuit comprising a portionof said first transistors, wherein each of said plurality of ECUscomprises a second circuit, said second circuit comprising a portion ofsaid second transistors, wherein each of said plurality of ECUscomprises a third circuit, said third circuit comprising a portion ofsaid third transistors, wherein each of said ECUs comprises a verticaldata bus, wherein said vertical data bus comprises greater than eightpillars and less than three hundreds pillars, wherein said vertical databus provides electrical connections between said first circuit and saidsecond circuit, wherein each of said ECUs comprises vertical controllines, wherein said vertical control lines comprise more than eighthundreds pillars, and wherein said vertical control lines provideelectrical connections between said second circuit and said thirdcircuit.
 2. The device according to claim 1, wherein said second levelis bonded to said first level, and wherein said bonded comprises oxideto oxide bonding regions and metal to metal bonding regions.
 3. Thedevice according to claim 1, wherein said third level comprises an arrayof memory cells, and wherein said second circuit comprises a memorycontrol circuit.
 4. The device according to claim 1, wherein said thirdlevel comprises an array of DRAM cells.
 5. The device according to claim1, wherein said first circuit comprises at least one processor.
 6. Thedevice according to claim 1, wherein said vertical data bus comprisesless than one hundred and twenty pillars.
 7. The device according toclaim 1, wherein each of said vertical control lines is connected to onehorizontal memory control line.
 8. A 3D device, the device comprising: afirst level comprising first transistors, said first level comprising afirst interconnect; a second level comprising second transistors, saidsecond level overlaying said first level; a third level comprising thirdtransistors, said third level overlaying said second level; a pluralityof electronic circuit units (ECUs), wherein each of said plurality ofECUs comprises a first circuit, said first circuit comprising a portionof said first transistors, wherein each of said plurality of ECUscomprises a second circuit, said second circuit comprising a portion ofsaid second transistors, wherein each of said plurality of ECUscomprises a third circuit, said third circuit comprising a portion ofsaid third transistors, wherein each of said ECUs comprises a verticaldata bus, wherein said vertical data bus comprises greater than eightpillars and less than three hundreds pillars, wherein said vertical databus provides electrical connections between said first circuit and saidthird circuit, wherein each of said ECUs comprises vertical controllines, wherein said vertical control lines comprise more than eighthundreds pillars, and wherein said vertical control lines provideelectrical connections between said second circuit and said thirdcircuit.
 9. The device according to claim 8, wherein said second levelis bonded to said first level, and wherein said bonded comprises oxideto oxide bonding regions and metal to metal bonding regions.
 10. Thedevice according to claim 8, wherein said second level comprises anarray of memory cells, and wherein said third circuit comprises a memorycontrol circuit.
 11. The device according to claim 8, wherein saidsecond level comprises an array of DRAM cells.
 12. The device accordingto claim 8, wherein said first circuit comprises at least one processor.13. The device according to claim 8, wherein said vertical data buscomprises less than one hundred and twenty pillars.
 14. The deviceaccording to claim 8, wherein each of said vertical control lines isconnected to one horizontal memory control line.
 15. A 3D device, thedevice comprising: a first level comprising first transistors, saidfirst level comprising a first interconnect; a second level comprisingsecond transistors, said second level overlaying said first level; athird level comprising third transistors, said third level overlayingsaid second level; a plurality of electronic circuit units (ECUs),wherein each of said plurality of ECUs comprises a first circuit, saidfirst circuit comprising a portion of said first transistors, whereineach of said plurality of ECUs comprises a second circuit, said secondcircuit comprising a portion of said second transistors, wherein each ofsaid plurality of ECUs comprises a third circuit, said third circuitcomprising a portion of said third transistors, wherein each of saidECUs comprises a vertical data bus, wherein said vertical data buscomprises greater than eight pillars and less than three hundredspillars, wherein said vertical data bus provides electrical connectionsbetween said first circuit and said second circuit, wherein said thirdlevel comprises an array of memory cells, and wherein said secondcircuit comprises a memory control circuit.
 16. The device according toclaim 15, wherein said second level is bonded to said first level, andwherein said bonded comprises oxide to oxide bonding regions and metalto metal bonding regions.
 17. The device according to claim 15, whereineach of said ECUs comprise vertical control lines, wherein each verticalcontrol line comprises more than eight hundreds pillars, and whereinsaid vertical control lines provide electrical connections between saidsecond circuit and said third circuit.
 18. The device according to claim15, wherein said third level comprise an array of DRAM cells.
 19. Thedevice according to claim 15, wherein said first circuit comprises atleast one processor.
 20. The device according to claim 15, wherein saidvertical data bus comprises less than one hundred and twenty pillars.